Enhancement: request caching

[Khaaz]

We could expect an implementation to cache and save all request that couldn't be sent to discord.
EG: Discord goes down and is non reachable. We would like to keep track of all github/gitlab request and send it back when discord is available.

This would use some kind of embeded DB (json/sqlite/other?). This should be configurable to not be a requirement if there is a need for additional package/infrastructure.